1. Field of Invention
The present invention relates to power converters, and more particularly, to time-based synchronous rectification in a power converter.
2. Description of Related Art
Power converters are essential for many modern electronic devices. Among other capabilities, power converters can adjust voltage level downward (buck converter) or adjust voltage level upward (boost converter). Power converters may also convert from alternating current (AC) power to direct current (DC) power, or vice versa. Power converters are typically implemented using one or more switching devices, such as transistors, which are turned on and off to deliver power to the output of the converter. Control circuitry is provided to regulate the turning on and off of the switching devices, and thus, these converters are known as “switching voltage regulators” or “switching voltage converters.” The power converters may also include one or more capacitors or inductors for alternately storing and outputting energy.
Switching voltage converters can be used in low power applications such as portable electronic devices (e.g., laptop computers, cell phones, etc.), for example, to convert a voltage at a higher level (e.g., 5V) to a voltage at a lower level (e.g., 1V). To maximize efficiency in switching voltage converters, it is desirable to prevent current from reversing in the output inductor. Reverse current flow at light load degrades efficiency by increasing the RMS current that flows through switching elements and the output inductor. This RMS current causes unnecessary losses.